Along an assembly line, various types of articles, such as for example, diapers and other absorbent articles, may be assembled by adding components to and/or otherwise modifying an advancing, continuous web of material. For example, in some processes, advancing webs of material are combined with other advancing webs of material. In other examples, individual components created from advancing webs of material are combined with advancing webs of material, which in turn, are then combined with other advancing webs of material. In some cases, individual components created from an advancing web or webs are combined with other individual components created from other advancing web or webs. Webs of material and component parts used to manufacture diapers may include: backsheets, topsheets, leg cuffs, waist bands, absorbent core components, front and/or back ears, and fastening components. Once the desired component parts are assembled, the advancing web(s) and component parts are subjected to a final knife cut to separate the web(s) into discrete diapers or other absorbent articles.
Some diaper components, such as leg elastics, barrier leg cuff elastics, stretch side panels, and waist elastics, are constructed from elastic laminates. Such elastic laminates may be assembled in various ways depending on the particular diaper design. For example, some elastic laminates may be constructed from one or more nonwoven substrates bonded to an elastic film. In some configurations, the elastic film may be stretched and then bonded with the nonwoven substrates to form an elastic laminate.
Elastic laminates may be characterized by the force for a given extension when used in a disposable absorbent article. The magnitude of the force required to extend the elastic laminate may vary between the first extension and subsequent extensions. In some configurations, the elastic laminate may include an elastic film that may comprise a base elastic film, such as a styrenic-block copolymer, and surface layers also known as skins. Such skins may help prevent interlayer adhesion when the elastic film is wound into a roll format for shipping and handling. In some configurations, the skins may be a polyolefin, which may be 0.5-5 microns thick. However, the polyolefin skins on the surface of the elastic film may cause the higher initial extension forces for an elastic laminate. Some manufacturers of films may apply processes to help reduce the initial extension force for a given displacement relative to subsequent extensions. For example, some manufactures of films may apply a process, sometimes referred to as “activation,” wherein the films are extended or stretched to create a plurality of cracks and tears in the skins at a microscopic scale. In turn, these cracks and tears may help reduce the skin contribution to the extension forces. In some configurations, activation operations are performed separate to the assembly process, such as for example, activating the films offline wherein the films may be stored until needed for production. For example, activation operations may be accomplished during the manufacture of the films, separately from converting lines that are dedicated to manufacturing elastic laminates the may be used in disposable absorbent articles. After manufacturing and activating the films, the films are delivered to the converting lines, such as in a form of continuous films wound onto a roll.
However, performing activation processes during film manufacture may be relatively inflexible and require extra processes and handling by the supplier of such films, which in turn, may add costs. For example, when implemented as an offline process, the tooling may require tight tolerances that are relatively more difficult to achieve when applied to relatively wide films. In addition, films may be plastically deformed by activation processes, such that the width of the activated film once relaxed is larger than the initial width. Such an increase in width may result in increased costs to the end user.
Consequently, it would be beneficial to provide methods and apparatuses for assembling elastic laminates that are configured to perform activation processes that may be performed online during the article assembly process.